[tarantool-patches] Re: [RFC 2/2] box/lua/console: Add support for lua output format

[Konstantin Osipov <kostja@tarantool.org>]

* Cyrill Gorcunov <gorcunov@gmail.com> [19/07/06 00:13]:

LGTM. @totktonada, please provide a more thorough review.

One question is what happens to the output on client reconnect.
Perhaps we should cache it on the client as well (this is the same
issue with console language).

> Historically we use YAML format to print results of operation to
> a console. Moreover our test engine is aiming YAML as a primary format
> to compare results of test runs. Still we need an ability to print
> results in a different fasion, in particular one may need to use
> the console in a REPL way so that the results would be copied and
> pased back to further processing.
> 
> For this sake we introduce that named "output" command which allows
> to specify which exactly output format to use. Currently only yaml
> and lua formats are supported.
> 
> To specify lua output format type
> 
>  | tarantool> \set output lua
> 
> in the console. lua mode supports line oriented output (default) or
> block mode.
> 
> For example
> 
>  | tarantool> a={1,2,3}
>  | tarantool> a
>  | ---
>  | - - 1
>  |   - 2
>  |   - 3
>  | ...
>  | tarantool> \set output lua
>  | true
>  | tarantool> a
>  | {1, 2, 3}
>  | tarantool> \set output lua,block
>  | true
>  | tarantool> a
>  | {
>  |   1,
>  |   2,
>  |   3
>  | }
> 
> By default YAML output format is kept for now, simply to not
> break the test engine. The output is bound to a session, thus every
> new session should setup own conversion if needed.
> 
> Since serializing lua data is not a trivial task we use "serpent"
> third party module to convert data.
> ---
>  src/box/CMakeLists.txt  |  1 +
>  src/box/lua/console.c   | 26 ++++++++++++
>  src/box/lua/console.lua | 90 ++++++++++++++++++++++++++++++++++++++++-
>  src/lua/help_en_US.lua  |  1 +
>  4 files changed, 117 insertions(+), 1 deletion(-)
> 
> diff --git a/src/box/CMakeLists.txt b/src/box/CMakeLists.txt
> index 481842a39..4b037094a 100644
> --- a/src/box/CMakeLists.txt
> +++ b/src/box/CMakeLists.txt
> @@ -11,6 +11,7 @@ lua_source(lua_sources lua/feedback_daemon.lua)
>  lua_source(lua_sources lua/net_box.lua)
>  lua_source(lua_sources lua/upgrade.lua)
>  lua_source(lua_sources lua/console.lua)
> +lua_source(lua_sources ../../third_party/serpent/src/serpent.lua)
>  lua_source(lua_sources lua/xlog.lua)
>  lua_source(lua_sources lua/key_def.lua)
>  lua_source(lua_sources lua/merger.lua)
> diff --git a/src/box/lua/console.c b/src/box/lua/console.c
> index cefe5d863..57e7e7f4f 100644
> --- a/src/box/lua/console.c
> +++ b/src/box/lua/console.c
> @@ -46,6 +46,8 @@
>  #include <stdlib.h>
>  #include <ctype.h>
>  
> +extern char serpent_lua[];
> +
>  static struct luaL_serializer *luaL_yaml_default = NULL;
>  
>  /*
> @@ -431,6 +433,24 @@ console_session_push(struct session *session, uint64_t sync, struct port *port)
>  				     TIMEOUT_INFINITY);
>  }
>  
> +static void
> +lua_serpent_init(struct lua_State *L)
> +{
> +	static const char modname[] = "serpent";
> +	const char *modfile;
> +
> +	lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
> +	modfile = lua_pushfstring(L, "@builtin/%s.lua", modname);
> +	if (luaL_loadbuffer(L, serpent_lua, strlen(serpent_lua), modfile)) {
> +		panic("Error loading Lua module %s...: %s",
> +		      modname, lua_tostring(L, -1));
> +	}
> +
> +	lua_call(L, 0, 1);
> +	lua_setfield(L, -3, modname);  /* _LOADED[modname] = new table */
> +	lua_pop(L, 2);
> +}
> +
>  void
>  tarantool_lua_console_init(struct lua_State *L)
>  {
> @@ -471,6 +491,12 @@ tarantool_lua_console_init(struct lua_State *L)
>  	};
>  	session_vtab_registry[SESSION_TYPE_CONSOLE] = console_session_vtab;
>  	session_vtab_registry[SESSION_TYPE_REPL] = console_session_vtab;
> +
> +	/*
> +	 * Register serpent serializer as we
> +	 * need it inside console REPL mode.
> +	 */
> +	lua_serpent_init(L);
>  }
>  
>  /*
> diff --git a/src/box/lua/console.lua b/src/box/lua/console.lua
> index f922f0320..7c3b608cb 100644
> --- a/src/box/lua/console.lua
> +++ b/src/box/lua/console.lua
> @@ -1,5 +1,6 @@
>  -- console.lua -- internal file
>  
> +local serpent = require('serpent')
>  local internal = require('console')
>  local session_internal = require('box.internal.session')
>  local fiber = require('fiber')
> @@ -13,7 +14,9 @@ local net_box = require('net.box')
>  local YAML_TERM = '\n...\n'
>  local PUSH_TAG_HANDLE = '!push!'
>  
> -local function format(status, ...)
> +local output_handlers = { }
> +
> +output_handlers["yaml"] = function(status, opts, ...)
>      local err
>      if status then
>          -- serializer can raise an exception
> @@ -33,6 +36,71 @@ local function format(status, ...)
>      return internal.format({ error = err })
>  end
>  
> +output_handlers["lua"] = function(status, opts, ...)
> +    local data = ...
> +    --
> +    -- Don't print nil if there is no data
> +    if data == nil then
> +        return ""
> +    end
> +    --
> +    -- Map internals symbols which serpent don't know
> +    -- about into known representation.
> +    local map_symbols = function(tag, head, body, tail, level)
> +        local symbols = {
> +            ['"cdata<void %*>: NULL"']  = 'box.NULL'
> +        }
> +        for k,v in pairs(symbols) do
> +            body = body:gsub(k, v)
> +        end
> +        return tag..head..body..tail
> +    end
> +    local serpent_opts = {
> +        custom  = map_symbols,
> +        comment = false,
> +    }
> +    if opts == "block" then
> +        return serpent.block(..., serpent_opts)
> +    end
> +    return serpent.line(..., serpent_opts)
> +end
> +
> +local function output_verify_opts(fmt, opts)
> +    if opts == nil then
> +        return
> +    end
> +    if fmt == "lua" then
> +        if opts ~= "line" and opts ~= "block" then
> +            local msg = 'Wrong option "%s", expecting: line or block.'
> +            error(msg:format(opts))
> +        end
> +    end
> +end
> +
> +local function output_save(fmt, opts)
> +    --
> +    -- Output format descriptors are saved per
> +    -- session thus each console may specify own
> +    -- specifics.
> +    box.session.storage.console_output = {
> +        ["fmt"] = fmt, ["opts"] = opts
> +    }
> +end
> +
> +local function format(status, ...)
> +    local d = box.session.storage.console_output
> +    --
> +    -- If there was no assignment yet provide
> +    -- a default value; for now it is YAML
> +    -- for backward compatibility sake (don't
> +    -- forget about test results which are in
> +    -- YAML format).
> +    if d == nil then
> +        d = { ["fmt"] = "yaml", ["opts"] = nil }
> +    end
> +    return output_handlers[d["fmt"]](status, d["opts"], ...)
> +end
> +
>  --
>  -- Set delimiter
>  --
> @@ -71,11 +139,31 @@ local function set_language(storage, value)
>      return true
>  end
>  
> +local function set_output(storage, value)
> +    local fmt, opts
> +    if value:match("([^,]+),([^,]+)") ~= nil then
> +        fmt, opts = value:match("([^,]+),([^,]+)")
> +    else
> +        fmt = value
> +    end
> +    for k, _ in pairs(output_handlers) do
> +        if k == fmt then
> +            output_verify_opts(fmt, opts)
> +            output_save(fmt, opts)
> +            return true
> +        end
> +    end
> +    local msg = 'Invalid format "%s", supported languages: lua and yaml.'
> +    return error(msg:format(value))
> +end
> +
>  local function set_param(storage, func, param, value)
>      local params = {
>          language = set_language,
>          lang = set_language,
>          l = set_language,
> +        output = set_output,
> +        o = set_output,
>          delimiter = set_delimiter,
>          delim = set_delimiter,
>          d = set_delimiter
> diff --git a/src/lua/help_en_US.lua b/src/lua/help_en_US.lua
> index d37b49bf7..4f0f7d65b 100644
> --- a/src/lua/help_en_US.lua
> +++ b/src/lua/help_en_US.lua
> @@ -8,6 +8,7 @@ To start the interactive Tarantool tutorial, type 'tutorial()' here.
>  Available backslash commands:
>  
>    \set language <language>   -- set language (lua or sql)
> +  \set output <format>       -- set output format (lua[,line|block] or yaml)
>    \set delimiter <delimiter> -- set expression delimiter
>    \help                      -- show this screen
>    \quit                      -- quit interactive console
> -- 
> 2.20.1
> 

-- 
Konstantin Osipov, Moscow, Russia